Depurination

Depurination is a chemical reaction of purine deoxyribonucleosides, deoxyadenosine and deoxyguanosine, and ribonucleosides, adenosine or guanosine, in which the β-N-glycosidic bond is hydrolytically cleaved releasing a nucleic base, adenine or guanine, respectively.

Loss of pyrimidine bases (cytosine and thymine) occurs by a similar mechanism, but at a substantially lower rate.

[1][2] When depurination occurs with DNA, it leads to the formation of apurinic site and results in an alteration of the structure.

[5] Hydrolytic depurination is one of the principal forms of damage to ancient DNA in fossil or subfossil material, since the base remains unrepaired.

This results in both loss of information (the base sequence), and difficulties in recovery and in vitro replication of the damaged molecule by the polymerase chain reaction.